Until now, seat occupancy detection methods and devices for on vehicle seats have primarily consisted of a rocker arranged below a cushion of a seat part of the vehicle seat, with a pressure sensor arranged below said rocker. See, e.g., DE 103 20 287 A1. As soon as the rocker, which due to necessarily being integrated in the seat part has a complicated structure with regard to its shape, is pushed downwards by a movement of the cushion part or of the seat part, the pressure sensor is activated and a seat movement is detected.
However, such a device for seat occupancy detection does not make it possible, or makes it possible only to a limited extent, to distinguish between a weight acting on the seat part due to a person sitting on the seat and a weight acting on the seat part due only to an object being placed on the seat part.
Although safety-related features of the vehicle, such as for example an immobilizer or the electronic activation of an ignition system of a vehicle for starting purposes, are dependent on the detection of such a seat occupancy, in the previous devices for seat occupancy detection an occupancy need not necessarily take place by a person in order to activate these safety-related features, i.e. for example to disengage an immobilizer or to electronically activate the ignition system for a starting process.
Accordingly, there is a need for a device for vehicle seat occupancy detection which makes it possible in a simple and reliable manner to distinguish between the weight of persons sitting on the seat and objects placed on the seat.